The invention relates to an apparatus on a carding machine for processing textile fibres, for example cotton, synthetic fibres and the like, with a cylinder. Generally, in such an apparatus, in the preliminary carding zone, after carding zone and/or underneath carding zone, covering elements lie opposite the cylinder clothing, and a fixed carding element is associated with at least one cover element, the spacing of the cylinder clothing with respect to the clothing of the fixed carding element (carding nip) being smaller than the spacing with respect to the cover element.
In practice, covering elements are located only a small distance apart from the clothed outer surface of the high-speed cylinder. In addition to cover plates without clothing there are also routinely present clothed fixed carding elements having at least one clothing strip. In many cases, relatively short non-clothed cover profiles extend tangentially to the cylinder clothing.
In a known apparatus (EP 0 687 754 A) a cylinder casing segment is provided which serves as support for three fixed carding bars. Upstream of the first (seen in the direction of rotation of the cylinder) fixed carding bar (clothing strip), the cylinder casing segment has a non-clothed extension piece which covers the cylinder. The surface of the extension piece is flat and extends parallel to the cylinder clothing. Furthermore, the spacing between the extension piece and the cylinder clothing in the circumferential direction of the cylinder is throughout larger than the spacing between the clothing of the fixed carding element and the cylinder clothing. In particular, the spacing of the end of the extension piece associated with the fixed carding element with respect to the clothing of the fixed carding element is substantial, and there is a step. As a result, air turbulence occurs upstream of the fixed carding element, which in an undesirable manner results in increased nep formation in the fibre material. A further problem is that the turbulence leads to an increased pressure difference at the fixed carding elements, to increased heating of the components involved, to higher fibre loading and to clogging of the clothing strips of the fixed carding elements.
It is an aim of the invention to provide an apparatus of the kind described at the beginning that avoids or mitigates the mentioned disadvantages, that especially reduces nep formation, allows improved carding work and gives a better carding result.